1. Field of the Invention
The present invention relates to a compressor for compressing a refrigerant suitable for use in, for example, an air conditioning system, a water heater, a car air conditioner, a showcase, a freezer and refrigerator, or a refrigeration unit such as an automatic dispenser.
2. Description of the Related Art
In such a conventional compressor, for example, in a multistage compression type rotary compressor of an inside intermediate-pressure type, refrigerant gas is drawn into a low pressure chamber side of a cylinder from a refrigerant introduction pipe via a suction port of a first rotary compression element. The refrigerant gas is then compressed by operations of a roller and a vane to become intermediate pressure, and is discharged from a high pressure chamber side of the cylinder through a discharge port and a noise eliminating chamber into a sealed container.
The intermediate-pressure refrigerant gas in the sealed container is drawn into the lower pressure chamber side of the cylinder from a suction port of a second rotary compression element, and then is subjected to a second stage compression by the operations of the roller and the vane to become high-temperature and high-pressure refrigerant gas. The refrigerant gas flows from the high pressure chamber side of the cylinder through the discharge port and the noise eliminating chamber, and is discharged from a refrigerant discharge pipe to the outside of the compressor to be supplied to a refrigerating cycle, such as an air conditioning system, where the refrigerant gas radiates heat and is condensed to enter an evaporator. In the evaporator, heat of the refrigerant gas is absorbed and the refrigerant gas is evaporated. Thereafter the refrigerant gas is drawn again into the first rotary compression element through the refrigerant introduction pipe. This cycle is repeated.
In a sealed-type electric compressor with such an arrangement, a refrigerant introduction pipe or a refrigerant discharge pipe is connected to a cylindrical sleeve which is welded and fixed to a curved surface of a sealed container having a cylindrical shape. The typical conventional structure of the sleeve is shown in FIGS. 6 and 7.
A sleeve 141X as exemplified in FIG. 6 is made of iron material having large rigidity. A tapered tip end side of the sleeve 141X is attached to an outer wall surface of the sealed container made of iron by projection welding with its inner surface brazed and fixed to a pipe member 145X made of copper material having good ductility, but less rigidity than the iron, for connection with a refrigerant pipe.
A sealed pipe having its tip end leading to a cylinder of compression means existing in the sealed container is inserted into the inside of the pipe member 145X made of copper. Into the sealed pipe, a refrigerant introduction pipe or a refrigerant discharge pipe is further fitted and connected.
The sleeve 141X as exemplified in FIG. 7 has a tapered side part with a large thickness, which is attached to the sealed container by the projection welding.
In a compressor including a sleeve having a shape such as that shown in FIG. 6, since a sleeve body incorporates therein the pipe, the sleeve body itself becomes larger than the pipe. This disadvantageously results in an increased diameter of a part which is projection welded, which leads to reduction in the strength of resistance to pressure of the welded part. The method for fixing the pipe involves simply inserting the copper pipe into the sleeve body and brazing it thereto, thus making it difficult to attach the pipe to the sleeve body at the right angle with respect to the body. This causes a problem that attachment of the refrigerant introduction pipe and the like cannot be carried out constantly in the same way.
In a compressor including a sleeve having a shape such as that shown in FIG. 7, since a part of a sleeve that is subjected to the projection welding has a large thickness, when the sleeve is attached to a container body by welding, the container body is largely pushed, thereby disadvantageously resulting in large deformation of the container body.